Field of the Invention
The present invention relates to a battery pack, and particularly to a battery remaining power predicting device which predicts battery remaining power of a lithium ion rechargeable battery or the like.
Background Art
A rechargeable battery has been used in many devices, starting with a portable device. A battery management system for managing charging/discharging is essential therefor. In particular, it is necessary to more accurately recognize the operation time of the battery during the device operation. Therefore, a battery remaining power predicting device has been used.
A battery pack equipped with a related art battery remaining power predicting device is illustrated in FIG. 6. The related art battery remaining power predicting device 20 is equipped with a CPU 21 which performs a signal processing operation, a RAM 22 used upon the signal processing operation, an ADC 23 for detecting a battery voltage obtained by converting a battery voltage corresponding to one cell of the rechargeable battery 7 by a level translator 26, an ADC 24 for detecting a voltage developed across a current sense resistor 6 for detecting a current of the rechargeable battery 7, and a nonvolatile-memory 25 which stores characteristic data of the rechargeable battery, etc. therein in advance. The present battery remaining power predicting device determines the battery remaining power from the voltage of the rechargeable battery 7, a moving charge quantity obtained by a coulomb counter from the current value of the rechargeable battery 7 measured using the current sense resistor 6, etc. The high accuracy measurement of the voltage and current of the rechargeable battery 7 is essential for a high-accuracy remaining power prediction.
Paying particular attention to current measurement, the current sense resistor 6 is required to have a resistance value with high accuracy.
[Patent Document 1]
U.S. Pat. No. 6,789,026, specification